Enterprise storage systems currently available are typically proprietary storage appliances that integrate the storage controller functions and the storage media into the same physical unit. This centralized model makes it harder to independently scale the storage systems' capacity, performance and cost. Users can get tied to one expensive appliance without the flexibility of adapting it to different application requirements that may change over time. For small and medium scale enterprise, this may require substantial upfront capital cost. For larger enterprise datacenters, new storage appliances are added as the storage capacity and performance requirements increase. These appliances may operate in silos and impose significant management overhead.